126 - South Coast Plain : Natural Capital and Key Ecosystem Services

Introduction

The South Coast Plain NCA provides a wide range of benefits to society. Each is derived from the attributes and processes within the area. These benefits are known collectively as ‘ecosystem services’. The predominant services are summarised below. Further information on ecosystem services provided in the South Coast Plain NCA is contained in the ‘Analysis’ section of this website.

What is Natural Capital?

Natural capital means “the elements of nature that directly or indirectly produce value to people, including ecosystems, species, freshwater, land, minerals, the air and oceans, as well as natural processes and functions” (Natural Capital Committee, 2017).

It is helpful to consider natural capital in the form of a logic chain that represents the links between ecosystem assets, services, benefits and value to people. The figure below displays that logic chain. The quantity and quality of ecosystem assets (woodland, bogs, etc) support different types of ecosystem services, such as carbon sequestration or water filtration. These ecosystem services then provide different benefits to society, providing value for people. The figure also shows how management interventions, as well as pressures and drivers of change, influence this chain. Other capital inputs are also often needed for people to obtain the benefits from ecosystem services (a simple example is the processing of trees to produce wood products).

As an example, an area of woodland (ecosystem asset) may reduce air pollution created by traffic on a nearby road. This woodland is therefore improving air quality (ecosystem service) in the local area which results in cleaner air and improved health in the adjacent residential street (benefit). This cleaner air has a value because we know it impacts the health and wellbeing of communities.

Sometimes for ease of understanding, economic framing is used to give these benefits a monetary value. The figure below shows how natural capital assets support the provision of ecosystem services, benefits and value. The roots of the tree show how aspects of asset quality are critical to the provision of ecosystem services. The roots also show that geodiversity underpins the ecosystem assets and therefore the ecosystem services and benefits they can provide. It is important to remember that this diagram, and natural capital frameworks more generally, are a simplification of how nature works in practice.

Natural Capital within this NCA

In 2018, Natural England published ‘Natural Capital Indicators: for defining and measuring change in natural capital’ (Lusardi et al., 2018). This report identified key properties of the natural environment vital for the long-term sustainability of benefits, which can act as indicators of change.

These indicators are designed to inform our understanding of the state of our natural assets. The indicators highlight the importance of our natural assets for delivering which ecosystem service and the benefits they provide for society. The indicators and datasets identified in Natural England’s Natural Capital Indicators Project provide the foundation for the Natural Capital Atlas Profiles.

Natural England’s Natural Capital Atlas Profiles provide an “off the shelf” natural capital evidence base for each county or city region. They have a wide variety of uses with more information in the How to Start Using Your Natural Capital Atlas.

The Natural Capital indicators are presented on the map below by broad asset theme, displaying the natural capital within the NCA.

It is noted that not all indicators listed within the Natural Capital Atlas Profiles are included within the map as data is not yet available to measure them. Refer to the “Indicator Gaps and Limitations” of the Natural Capital Atlas Profiles for further information.

Natural Capital Atlas Profiles

The following Natural Capital Atlas Profiles cover counties within this NCA:
 

• 12: East Sussex
• 17: Hampshire and the Isle of Wight
• 41: West Sussex

Provisioning services (food, fibre and water supply)

Food provision: The fertile soils of the lower plain support intensive arable farming and horticulture, with some dairy, beef and poultry. Permanent grassland is a feature of the poorer quality land. Mixed farming occurs on the thicker gravel deposits. Fish are an important food source. Shellfish are harvested from the harbour areas and fish landed from the open sea. During the oyster fishing season of 2012/13, 60 tons of oysters were harvested from Chichester Harbour (Sussex Inshore Fisheries and Conservation Authority). The harbours are also vital nursery areas for species including bass, bream, mullet, sole and plaice.

Water availability: Public water supply relies on surface water abstraction and groundwater from the Lower Greensand aquifer and the Worthing and Chichester chalk blocks. Water supply is under pressure throughout the area. For information regarding the current state of water availability within this NCA, refer to the Environment Agency (Abstraction Licensing Strategy).

Genetic diversity: The Home Farm of the Goodwood Estate favours rare breeds such as pedigree Southdown sheep, continuing a tradition long held by the dukes of Richmond.

Regulating services (water purification, air quality maintenance and climate regulation)

Climate regulation: The soils in this NCA predominantly have low levels of soil carbon (0-5 per cent). However, there are some very small patches, in the west, that reach carbon levels of up to 20-50 per cent. The relatively large areas of flood plain grazing marsh have additional locked-up carbon stores, as do the small areas of woodland.

Regulating soil erosion: Lighter soils make up just under half of the NCA and exposed soils are at risk of erosion on sloping land, exacerbated where organic matter levels are low after continuous arable cultivation or where soils are compacted. Sand dune soils are very unstable, with the extent of erosion depending on the degree to which vegetation has stabilised the dune system.

Regulating water quality: For information regarding the current state of water quality within this NCA, refer to the Environment Agency (Draft river basin management plan maps).

Regulating water flow: Much of the flood storage capacity has been lost through drainage of marshlands and conversion to intensive agriculture or development both within and upstream of this NCA, particularly affecting the Arun’s wide flood plain. Many settlements within the NCA are protected by flood banks.
Policies to reduce flood risk include the storage of water within the Adur catchment on the South Downs (outside this NCA), as well as encouraging the creation of sustainable urban drainage systems and the River Lavant Flood Alleviation Scheme (Downs and Harbours Clean Water Partnership).

Pollination: Nearly 2,000 ha of grassland provides important sources of nectar for pollinating insects, along with hedges, which are vital for the success of many of the area’s horticultural crops.

Regulating coastal flooding and erosion: Large lengths of this complex stretch of coastline are in an unnatural form. Much of the coastal frontage has been developed so only limited sections of the shoreline are free to erode naturally, meaning little sediment material goes into the coastal system. As a result of higher water levels, ‘coastal squeeze’ will occur. This will lead to beaches, intertidal areas and amenity value being reduced or lost. Defences are in place to protect the vulnerable clay headland of Selsey Bill from erosion though not necessarily trying to lock the feature into its present size, shape and orientation.

Reclamation of former coastal lowland for development has produced many areas where the shoreline is artificially seaward of its natural position. Rising sea levels will increase the probability of flooding for low-lying areas. The relevant Shoreline Management Plans are pursuing an overall policy of ‘holding the line’ and ‘managed realignment’ such as at the scheme at Medmerry which was the first of its kind on the open coast. For information regarding current shoreline management within this NCA, refer to the Environment Agency (Shoreline management plans).

Cultural services (inspiration, education and wellbeing)

Sense of place/inspiration: Views of the sea and maritime and seaside influences generally have inspired artists from Oscar Wilde to Eric Coates, who was inspired to write ‘Sleepy Lagoon’ (the theme tune for BBC Radio 4’s Desert Island Discs) while watching the sea from Selsey.

Sense of history: The area is rich in historical evidence from all ages including the internationally important Fishbourne Roman Palace. Chichester has enjoyed continuous occupation since it was founded by the Romans as Noviomagus Reginorum, and is dominated by its medieval cathedral, described by Pevsner as ‘the most typical English cathedral’.6 The area has a long history of maritime activity. Portsmouth’s historic dockyard, with attractions including Nelson’s flagship HMS Victory and the Mary Rose, entices thousands of visitors to the area every year. Further east, a string of fishing villages grew into popular seaside towns from the Georgian period and include Bognor Regis, Littlehampton and Worthing.

Tranquillity: Tranquillity is a scarce but greatly prized resource within this heavily urbanised NCA. Only 7 per cent of area is classed as undisturbed, while 35 per cent of the area is classified as urban. Pockets of tranquillity are associated with the central rural areas, the Manhood Peninsula and undeveloped harbours, including Chichester Harbour AONB.

Recreation: Coastal and water-borne activities are popular in this NCA and are an important contributor to the local economy. Chichester Harbour alone has over 5,200 moorings and marina berths and 16 sailing clubs. Chichester Harbour AONB has approximately 1.5 million visitors each year. Walkers, cyclists, artists and birdwatchers all enjoy the area. Many just sit and enjoy the view. East Head is one of the most popular recreation sites in the South East. Along the coast, tourism is also vital to the economies of seaside towns such as Worthing and Littlehampton.

Biodiversity: Three per cent (1,700 ha) of the area is designated as Sites of Special Scientific Interest (SSSI) and there are four Special Protection Areas (SPA, two Special Areas of Conservation (SAC and four Ramsar sites. Priority habitats include around 2,000 ha of coastal and flood plain grazing marsh and 1,000 ha of reedbeds.

Chichester Harbour has been designated as a wetland of international importance under the Ramsar Convention (1971) as it regularly holds 20,000 or more wildfowl and waders in winter. It has the third largest population of dark-bellied Brent goose in the country (Wetland Bird Survey) and supports internationally important populations of dunlin and black-tailed godwit. It also has a small resident harbour seal population. Pagham, Langstone and Portsmouth harbours also have wildfowl numbers of national or international importance and the whole area is important for breeding terns. A survey of the fish population of Chichester Harbour carried out in 2004 by the University of Portsmouth recorded 32 species, with sand goby, painted goby and black bream the most abundant. Also numerous at some sites were bass, ballan wrasse and corkwing wrasse. Twenty-two species were identified in 2012. The harbours are also vital nursery areas for species such as bass, bream, mullet, sole and plaice which make use of the seagrass beds.

Geodiversity: This NCA includes the site of the remains of Homo heidelbergensis, the world-famous ‘Boxgrove Man’, found in river gravels overlying chalk in a gravel pit just outside Chichester. Terrace gravels marking the historic shore of the Solent River contain important Pleistocene vertebrate remains and Palaeolithic (Early Stone Age) artefacts.